1. Field of the Invention
The concept of mounting an outboard motor or engine rearwardly of the transom of a boat on an external transom bracket or outboard transom has been known for some time. Such brackets have long been used on such vessels as sailboats which are dependent upon the wind for power. Small outboard motors are typically mounted on outboard transoms attached to these boats to provide a source of auxiliary power. In recent years, the value of external outboard transom brackets has been realized both to increase boat performance and to create additional space in the boat. With the ever increasing interest in racing, it has been found that outboard transoms can be used to support large outboard motors to good advantage in increasing the speed and handling characteristics of racing boats. Such brackets are simple in design and are sized and fabricated to bolt to the transom of the boats and safely carry an outboard motor of selected size and horsepower.
The performance of a boat is enhanced by an outboard transom because the motor is mounted away from the boat transom and the lower unit of the motor therefore projects into quieter water. Since the water which rushes past the boat hull at the point where the bottom joins the boat transom is forced upwardly, a turbulence develops at this point and extends rearwardly of the boat transom. This turbulence decreases with increasing distance from the boat transom. It is well known that a propellor-driven boat performs best when the propellor is rotating nearest the surface of water which is subjected to minimum turbulence and aeration. This optimum propellor location effects minimum propellor cavitation and ventilation and is realized when the outboard motor is mounted higher than it would normally be positioned on the transom of a boat and is located rearwardly of the transom. This propellor location advantage is increased when the outboard motor is mounted on an external transom bracket or outboard transom which is adjustable such that the motor can be raised or lowered with respect to the boat transom in order to optimize boat performance in any given condition of wind and water.
2. Description of the Prior Art
Several designs for external transom brackets are known in the art. Land and Sea, Inc. of North Salem, N.H., has developed an external transom bracket which includes a transom plate with a hydraulically actuated motor mount bracket for adjusting the height of an outboard motor with respect to the boat transom. A similar device is manufactured by G & M Enterprises, Inc. of El Dorado, Ark. A more simple, manually operated adjustable outboard transom is manufactured by Chaparral Marine Products, Inc. of Onalaska, Tex., which device is characterized by a transom mount plate and a pair of sliding motor mount brackets which are adjustably secured to the transom mount plate. The adjusting mechanism includes a pair of threaded turnbuckles, each having one end secured to a motor mount bracket and the other end attached to the transom mount plate, respectively, with a threaded collar for upward and downward adjustment of the threaded rod and motor mount brackets with respect to the boat transom. Similar manually operated devices have been designed by T-H Marine Supply Company of Madison, Ala. and Performance Plus Company of Torrance, Calif.
It is an object of this invention to provide a new and improved adjustable outboard transom which includes a fixed set of plates attached to the transom of a boat, a pair of cooperating movable plates and a cable wound on a shaft connecting the fixed plates with the ends of the cables attached to the movable plates to facilitate raising and lowering of the movable plates with respect to the fixed plates by selectively winding and unwinding the cable on the shaft.
Another object of the invention is to provide a new and improved adjustable outboard transom bracket which includes a pair of transom mount brackets secured to the transom of a boat and a pair of motor mount brackets in sliding attachment to the transom mount brackets. A shaft rotably joins the transom mount brackets, a cable is wound on the shaft and each end of the cable is anchored to one of the motor mount brackets. A ratchet and pawl mechanism is located in cooperation with the shaft, to facilitate incremental rotation of the shaft and adjustment of the height of the motor mount brackets and outboard motor with respect to the transom mount brackets and the boat transom.
Another object of this invention is to provide a jack plate mechanism or adjustable outboard transom which serves as an external transom bracket for a boat and uses a cable wound on a rotating shaft carried by fixed transom mount brackets to raise and ower a pair of cooperating motor mount plates anchoring the ends of the cable.
Yet another object of the invention is to provide an external transom apparatus for vertical adjustment of an outboard motor, which apparatus includes a pair of slotted transom plates secured to the transom of a boat in spaced relationship and a pair of motor mount plates cooperating in sliding relationship with the transom plates by means of bolts attached to the motor mount plates and extending through the slots in the transom plates and further including a shaft rotatably carried by the transom plates and a cable wound on the shaft and anchored at the ends to the motor mount plates.
Still another object of the invention is to provide an adjustable outboard transom which serves as an external transom bracket and includes a set of movable brackets slidably mounted on a set of fixed brackets secured to the transom of a boat, the slidably mounted, movable brackets relatively movable with respect to the fixed brackets by means of a ratchet and cable mechanism in cooperation with a rotating shaft joining the fixed brackets.